Condition detectors such as smoke, gas, heat or fire detectors are commonly found today in buildings of all types. Many municipalities require installation of such detectors in buildings. Some of these detectors are AC-powered. Others are battery-powered. Some include a combination of AC power and battery backup power.
Battery-powered detectors, while very convenient and easy to install, have suffered from the drawback that a user of the building might not realize the unit needs a battery or that battery power may be low. Typically, such batteries are merely replaced by the user. Detectors commonly are powered by standard dry cell or alkaline type batteries, such as nine-volt batteries.
To assure the effectiveness of the batteries, many detectors have audible alarms to indicate low battery power, or test circuits to periodically test the battery power. Nevertheless, such detectors require that batteries be periodically replaced in order for the detector to properly operate. Unfortunately, users do not always have spare batteries readily available, and often detectors will go without power until a battery can be located and placed in the detector.
Thus, there continues to be a need for a cost effective and reliable detector having a battery with an extended life.